I have purchased Wasabi root from Pacific Farms (http://www.freshwasabi.com/) It was very nice when grated properly, but it was milder than the fresh wasabi root that you find imported from Japan at the finest restaurants in the US, like Masa in NYC and Matsuhisa in LA.

When I get a little OCD I think about ordering some Japanese wasabi via one of my Japanese chef friends that gets it regularly. I suppose that if my Japanese were better I could buy it directly from Japan. :

)

Alternatively, as you are aware, you can buy authentic wasabi paste in tubes at many Asian markets and online from Catalina Offshore Products (http://www.catalinaop.com/index.htm) which also sells excellent sushi grade fish.

In today's Post Weekend section, Eve Zibart reports that Perry's in Adams Morgan also offers fresh wasabi at $3/serving. According to the article, they have a new sushi chef with new offerings and this guy's (japanese) formerly from NYC and also Matuba.